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Biomedical subjects

P J Hubner

Publications and source records attributed to P J Hubner.

At least 19 recordsLinked to original sources

The Subcutaneous Heparin and Angioplasty Restenosis Prevention (SHARP) trial. Results of a multicenter randomized trial investigating the effects of high dose unfractionated heparin on angiographic restenosis and clinical outcome.

OBJECTIVES: We sought to determine whether 12,500 IU of unfractionated heparin given subcutaneously twice daily for 4 months after percutaneous transluminal coronary angioplasty beneficially influences the subsequent rate of angiographic restenosis and the incidence of clinical events. BACKGROUND: Heparin has been shown to exhibit powerful antiproliferative effects against smooth muscle cells in several animal models. METHODS: A randomized trial with blinded data analysis was undertaken to assess the effect of unfractionated subcutaneous heparin on angiographic restenosis after coronary angioplasty. After successful angioplasty, patients were randomized to receive no heparin or 12,500 IU of heparin given subcutaneously twice daily for 4 months. Quantitative coronary angiography was performed before angioplasty, immediately after angioplasty and at follow-up ("early" [before 4 months] or electively [at 4 months]). RESULTS: The study group comprised 339 patients, 167 randomly assigned to receive heparin, 172 to receive no heparin. Repeat cardiac catheterization was performed in 90% of randomized patients. At early and elective restudy (mean 4.2 months), the mean +/- SD difference in minimal lumen diameter between the postangioplasty and follow-up measurement was -0.55 +/- 0.58 mm for the no heparin group and -0.43 +/- 0.59 mm for the heparin group (p = NS). Clinical events during the follow-up period did not differ significantly between groups: fatal myocardial infarction (1 patient in each group), coronary bypass grafting (5 patients in each group), repeat angioplasty (12 in the no heparin, 6 in the heparin group), angina at 4-month assessment (33% in the no heparin, 32% in the heparin group). CONCLUSIONS: Long-term treatment with high dose subcutaneous heparin (12,500 IU twice daily) for 4 months did not favorably influence angiographic or clinical outcome after coronary angioplasty.

Angioplasty, Balloon, Coronary

Gated technetium-99m methoxy-isobutylisonitrile perfusion imaging.

Technetium-99m methoxy-isobutylisonitrile, has been shown to be a useful perfusion agent for detecting coronary artery disease. Gated acquisition of perfusion images may remove motion artefact and improve detection. We compared the results of sensitivity and specificity for detecting coronary artery disease using perfusion images from the whole cardiac cycle (ungated) or from end-diastolic (gated) frames in 46 subjects, 31 with significant coronary disease and 15 with normal coronary arteries. There was no significant difference in detection of patients with coronary disease between the ungated and end-diastolic images: 25/31 with the ungated image and 28/31 with the end-diastolic. An improvement was made in detecting defects in the left anterior descending artery territory: 17/20 with the end-diastolic vs 11/20 with the ungated image (P less than 0.05) and in the right coronary artery region: 16/21 vs 10/21 (P less than 0.05), with an overall improvement in detecting regions supplied by stenosed coronary arteries: 45/55 end-diastolic vs 31/55 ungated (P less than 0.01). These results suggest use of the end-diastolic frame can significantly enhance the diagnostic capacity of methoxy-isobutylisonitrile perfusion imaging.

Adult

Cardiac failure secondary to hypocalcaemia of nutritional osteomalacia.

A 41-year-old Asian woman presented with mild congestive cardiac failure, initially controlled with a small dose of diuretic. Subsequently there was a marked deterioration in her condition with severe cardiac failure resistant to treatment. At this time biochemistry revealed a hyperphosphataemic variety of osteomalacia. Her cardiac failure improved promptly on correcting the hypocalcemia. Although hypocalcaemia is a recognised cause of cardiac failure it has not been described in privational osteomalacia.

Adult

Evaluation of changes in myocardial function on exercise in patients with coronary artery disease using gated MIBI scintigraphy.

Technetium-99m-methoxy-isobutyl-isonitrile (MIBI) is a myocardial perfusion agent which allows simultaneous assessment of left ventricular function. We evaluated left ventricular (LV) function with exercise using a new method of myocardial profiling in 43 patients with chest pain. Twenty-eight had significant coronary artery disease and 15 were normal on coronary angiography. Results were compared to equilibrium radionuclide ventriculography. MIBI fractional shortening (FS) correlated well with ejection fraction (EF) on exercise (r = 0.79, P = less than 0.001). There was also a good correlation between changes in global function from rest to exercise (r = 0.82, P = less than 0.001) with a sensitivity of diagnosing CAD of 71% and specificity of 80%. New regional wall abnormalities were detected in 25/28 with CAD with a sensitivity of 89% and specificity of 60%. There was also a close correlation between mean diameters measured with gated MIBI scans and volumes measured with RNV, end-diastolic diameter (EDD) versus end-diastolic volume (EDV) r = 0.78 (P = less than 0.001) at rest and r = 0.74 (P = less than 0.001) on exercise and end-systolic diameter (ESD) versus end-systolic volume (ESV) r = 0.72 (P = less than 0.001) at rest and r = 0.72 (P = less than 0.001) on exercise. This produced a sensitivity for detecting CAD of 79% and a specificity of 73%. These results show that gated MIBI scanning on exercise provides information comparable to RNV so enhancing the diagnostic usefulness of MIBI.

Adult

Gated 99Tcm-MIBI myocardial function imaging.

The introduction of the 99Tcm isonitrile perfusion agents has provided improved myocardial image quality with conventional imaging equipment allowing improved edge definition on gating. We evaluated left ventricular wall motion in 46 patients using gated 99Tcm-2-methoxy-2-methyl-isopropyl-1-isonitrile (MIBI) scintigraphy. Using a method of myocardial profiles in four axes, global and regional fractional shortening (FS) were assessed. A good correlation was found between FS in the left anterior oblique (LAO) 40 degrees projection and ejection fraction (EF) on gated radionuclide ventriculography (r = 0.81, P less than 0.001). This was improved by using FS in two planes, LAO 40 degrees and anterior (r = 0.88, P less than 0.001). There was also a good correlation between FS in two planes and EF on cine-angiography (r = 0.72, P less than 0.001). There was good intra- and interobserver agreement with the studies. Assessment of myocardial function using gated MIBI imaging and myocardial profiles provides useful additional information to the perfusion scan, thus enhancing the diagnostic usefulness of the agent.

Adult

Percutaneous transluminal coronary angioplasty in elderly patients: a comparison with younger patients.

Twenty-nine patients of 287 undergoing percutaneous transluminal coronary angioplasty (PTCA) were over 65 years old. These patients, mean age 67.2 years, were compared with 258 younger patients who had a mean age of 52.6 years. The primary success rate was 76% for the older and 79% for the younger patients. The rates for vessel occlusion, myocardial infarction, emergency surgery, and restenosis were similar in the two groups. When vessel occlusion occurred the results were more serious in the elderly and led to a fatality of 7%, compared with 0.4% for the younger patients. At 6 months' follow-up, 69% of those over 65 and 74% of those under 65 showed improvement in anginal symptoms. PTCA in older patients has similar immediate and short-term results to those in younger patients. However if complications occur, older patients have a higher fatality rate.

Adult

99mTc hexakis-t-butyl isonitrile (TBI): an agent for the diagnosis of coronary artery diseases.

Basic and clinical studies were undertaken to determine pharmacokinetic mechanisms, blood flow-related characteristics and potential clinical utility of the 99mTc hexakis-t-butyl isonitrile (TBI) in the non-invasive diagnosis of ischemic heart diseases. Pharmacokinetic studies with TBI in animals demonstrated a high initial lung, heart and liver uptake. The lung clears at a relatively faster rate, the activity in the heart remained constant with a buildup of activity in the liver. These pharmacokinetic characteristics allowed for a myocardial imaging at 30-45 min post-injection at rest. The regional myocardial distribution of TBI was shown to be linearly related to microsphere-determined regional myocardial blood flow with a redistribution potential in transient ischemic myocardium (i.e., mimics 201Tl). The first pass extraction fraction (in vitro) for TBI was shown to be nearly 100% and independent on flow levels. In general, the slow tissue clearance rate or the lack of it might be due to the high degree of lipophilicity with the complete lack of any hepatic or extrahepatic metabolism to a less lipophilic metabolite. The complex demonstrated a high degree of cardiac membrane association. The net extraction in isolated heart slices was shown to be dependent on pH and temperature, independent of energy. The clinical studies demonstrated a similar pharmacokinetic pattern to the animal studies and documented the perfusion and ventricular function utility of TBI in the diagnosis of ischemic heart diseases.

Adult

Long term use of enalapril in the treatment of patients with congestive heart failure.

Fifty-five patients of both sexes, aged 39-72, suffering from congestive heart failure of varying aetiology were admitted to a double blind study in which enalapril given in a dose of 5-10 mg twice daily or placebo was added to existing medication. A significant increase in exercise performance (P less than 0.004) was seen in the group treated with enalapril, an improvement which was still evident after 24 weeks of therapy. No significant difference was seen between the mean ejection fractions but subjective assessment suggested improvement in the enalapril-treated group.

Adult

Assessment of dermal glyceryl trinitrate and isosorbide dinitrate for patients with angina pectoris.

Dermal nitrate preparations are claimed to be useful in the treatment of angina, as their slow absorption by-passing the liver leads to a sustained action. Ten patients with angina were exercised on a treadmill after dermal application of 16.64 mg glyceryl trinitrate or 100 mg isosorbide dinitrate or placebo. Exercise duration was significantly increased at one and three hours for both nitrate preparations but not at six hours after application. The calculated workload achieved was significantly increased (p less than 0.01) at one and three hours for both preparations and at six hours (p less than 0.05) for isosorbide dinitrate. Headaches were common with glyceryl trinitrate cream. The dermal nitrate preparations studied had a duration of antianginal action similar to that of oral nitrate tablets. Aside from their value when the oral route cannot be used or absorption may be delayed, dermal nitrate preparations have no advantage over oral preparations for angina pectoris.

Administration, Topical